3215 WS WS3 40V/1.5A Step-down High Brightness LED Driver Features Description The WS3215 is a continuous conduction mode inductive ■ Simple low parts count ■ Wide input voltage range：8V to 40V step-down converter.designed for driving single or multiple series LED efficiently from a voltage source ■ Up to 1.5A output current higher than the total LED chain voltage. The device ■ Output current limit protection operates from an input supply between 8V and 30V and ■ Over temperature protection ■ Single pin on/off and brightness control using DC provides an external adjustable output current of up to 1.5A.Depending upon supply voltage and external Voltage or PWM ■ Typical 5% output current accuracy ■ Inherent open-circuit LED protection components, the WS3215 can provide more than 10 watts of output power. The WS3215 includes the power switch and a high-side output current sensing circuit .which uses ■ High efficiency (up to 97% ) ■ Adjustable LED constant current an external resistor to set the nominal average output current, and a dedicated DIM input accepts either a DC voltage or a wide range of pulsed dimming. Applying a Applications voltage of 0.3V or lower to the DIM pin turns the output off and switches the device into a low current standby state. ■ MR16 LEDs WS3215 using SOT89-5 package . ■ Automotive lighting ■ Low Voltage industrial lighting ■ illuminated signs Typical Application Circuit Rev.1.0 July.2011 Copyright@Winsemi Microelectronics Co., Ltd., All right reserved. 3215 WS WS3 Pin Definition and Device Marking Pin Function Description Pin Name Pin No. Pin Type Function Description SW 1 Output Drain terminal of internal Power MOSFET. GND 2 Power Signal and Power GND. DIM CSN VIN Exposed PAD 3 4 5 6 Floating Used for enabling Switch and Dimming with either a DC voltage or PWM input signal . Current Used for high-side output current sensing with an external sensing Monitoring resistance between CSN and VIN. Frequency Power supply input. Bypass with capacitor as close to the device as Setting possible . Floating Connected to GND for thermal considerations and pasted on PCB for reducing thermal resistance. Block Diagram 2/9 Steady, keep you advance 3215 WS WS3 Ordering Information Package SOT89-5 Pb-free IC Marking Information Purchasing Device Name WS3215 TP WS3215 Recommended Operating Condition Symbol Parameter Value Unit VIN Input voltage 8~40 V TA Operating temperature -20~85 ℃ Absolute Maximum Ratings ( Note 1) Symbol Parameter Value Unit VIN DC Supply Voltage -0.3~50 V SW Drain voltage of internal Power MOSFET -0.3~50 V Output current sensing voltage(relative CSN toVIN) DIM Switch enable and Dimming Voltage Isw V 0.3~-6.0 -0.3~6.0 V Maximum Output Current 1.8 A PDMAX Power Dissipation(Note 2) 1.5 W PTR Thermal Resistance,SOT89-5(θJA) 45 ℃/W TJ Junction Operating Temperature -40 to 150 ℃ TSTG Storage Temperature -55 to 150 ℃ Note1：Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2：Higher temperature leads to the necessary decreasing of maximum power dissipation. It also decided by both TJMAX, θJA,and ambient temperature TA. The maximum accepted power is formulated as PDMAX = (TJMAX -TA)/ θJA or the value among the lower ones in the absolute maximum rating. ESD Information Symbol VESD-HBM VESD-MM Parameter Value Human body model on all pins(Discharge with a 100pF capacitor through a 1.5kΩ resistance.) Machine model on all pins Unit 4 400 KV V 3/9 Steady, keep you advance 3215 WS WS3 Electrical Characteristics Characteristics((VIN=12V,T=25℃.(unless otherwise specified))（Note3，4） Symbol Parameter Test Conditions Min - 8 Typ Max Unit 40 V VIN Supply Voltage VUVLO VIN UVLO Threshold VIN Dscreasing 6.8 V VUVLO,HYS VIN UVLO Hysteresis VIN Increasing 500 mV FSW Maximal Oscillating Frequency 1 MHz 105 mV Sensing Current VCSN Average Sensing Voltage VCSN_hys Sensing Voltage Hysteresis ICSN Input Current from CSN VIN-VCSN 95 100 ±10 % VIN-VCSN=50mV 8 uA Turn-off Current VDIM<0.3V 50 uA VDIM Internal Supply Voltage DIM floating 5 V VDIM_H High Level for DIM Input Voltage VDIM_L Low Level for DIM Input Voltage VDIM_DC Dimming Rang with a DC Voltage fDIM Maximal PWM Dimming Frequency Turn-off Current IOFF DIM Input Duty Range of PWM Dimming fOSC=500kHz 0.02% PWM Dimming Ratio at low frequency Duty Range of PWM Dimming PWM Dimming Ratio at high frequency Leakage Current 2.5 V 50 kHz 1 4% 1 1.2 MΩ VDIM= 0 4.2 uA VIN =24V 0.5 VIN =12V 0.5 internal Supply Voltage IDIM_L V 25:1 Pull-up Resistance between DIM and RDIM 0.3 5000:1 fDIM =20KHz at high frequency DPWM_HF V 0.5 fDIM =100Hz at low frequency DPWM_LF 2.5 Switching RSW SW Turn-on Resistance ISWmean SW Continuous Current ILEAK SW Leakage Current 0.5 Ω 1.5 A 5 uA Thermal Protection TSD OTP Threshold 160 ℃ TSD_hys OTP Hysteresis 20 ℃ Note 3：Typical numbers are measured at 25°C as standard parameter. Note 4 ： In this datasheet, design methods, measurement and statistical analysis guarantee the typical value while measurement guarantees the range between the minimum and maximum. 4/9 Steady, keep you advance 3215 WS WS3 Typical Operating Characteristics Efficiency Eff./% L=47uH,Rs=0.27ohm 100.00 95.00 Eff.7 LED 90.00 Eff.3 LED 85.00 80.00 Eff.1 LED 75.00 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Vin/V Vdim vs VIN 5 Vdim/V 4 3 2 1 0 0 5 10 15 20 25 30 35 40 Vin/V 5/9 Steady, keep you advance 3215 WS WS3 6/9 Steady, keep you advance 3215 WS WS3 7/9 Steady, keep you advance 3215 WS WS3 Operation Description resistance, the LED output current can be controlled within 5% variation. A dedicated DIM input accepts a wide Applying WS3215 with inductor (L) and current sensing range of a DC voltage or pulsed dimming. Applying a resistance （RS）forms a self-oscillating step-down continuous voltage of 2.5V or higher to the DIM pin will turn on the current mode inductive LED controller. When Vin increases at power MOSFET completely, however, 0.3V or lower will the beginning, LED output current are zero initially through turn the output off. Therefore, it is available to receive a inductor, sensing resistance. Meanwhile, the CS comparator PWM dimming frequency range from 100Hz to 20KHz. turns high, the voltage of SW is low and the internal power Otherwise, an external resistance can be used to set the MOSFET is conductible. Through the external components LED output current. Linking with the internal pull-up and internal power MOSFET to GND, output current gets resistance (typically 1.2 Mohm) , which is connected to the greater with a constant rate determined by the voltage inner regulated 5V, a voltage applied to the DIM can be difference between inductor’s two terminals, then generate a achieved. By changing the ratio between the outer and sensing voltage on the RS. If (Vin-Vcsn)>110mV, CS inner resistance, the dimming voltage can be different and comparator turns low and internal power MOSFET turn off, the brightness of LED can be adjustable. state can not change until (Vin-Vcsn)<90mV. As a result, the During the turn-off phase, the quiescent current is only Average LED output current can be caculated by the following 60uA although the inner reference module is still at work.. equation: 0.09 + 0.11 0.1 Iout = = Rs 2 × Rs For the consideration of reliability, over-temperature protection in WS3215 is necessary. It avoids the WS3215 suffering over-temperature damage and guarantees the High-side current sensing circuit is applied for less maximum LED output current after recovery to normal. external components. With 1% accuracy of sensing 8/9 Steady, keep you advance 3215 WS WS3 SOT 89 ge Dimension SOT89 89--5 Packa Package 符号 A A1 b b1 C D E E1 e L 最小 毫米 典型 最大 1.40 1.50 1.60 0.30 0.40 0.50 0.36 0.42 0.48 0.41 0.47 0.53 0.38 0.40 0.43 4.40 4.50 4.60 — — 4.25 2.40 2.50 2.60 1.40 1.50 1.60 0.80 — — 9/9 Steady, keep you advance